# CVE-2020-1625: Junos OS: Kernel memory leak in virtual-memory due to interface flaps > Kernel memory leak in Junos OS causes extended denial of service when IRB interfaces flap, requiring monitoring and patching by network administrators. - **Severity:** Medium 6.5 (`CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H`) - **Exploited in the wild:** Not known - **Login needed:** Not needed - **Attackable:** Local or same network only - **Victim action needed:** Not needed - **Fix available:** No - **Published:** 8 Apr 2020 - **Updated:** 17 Sep 2024 - **Also known as:** GHSA-7w5f-39wq-4475 ## What is CVE-2020-1625? CVE-2020-1625 is a medium-severity denial of service vulnerability in Juniper Junos, published on 8 Apr 2020. It can only be exploited from the same machine or local network, with no action from the victim. ### Official description The kernel memory usage represented as "temp" via 'show system virtual-memory' may constantly increase when Integrated Routing and Bridging (IRB) is configured with multiple underlay physical interfaces, and one interface flaps. This memory leak can affect running daemons (processes), leading to an extended Denial of Service (DoS) condition. Usage of "temp" virtual memory, shown here by a constantly increasing value of outstanding Requests, can be monitored by executing the 'show system virtual-memory' command as shown below: user@junos> show system virtual-memory |match "fpc|type|temp" fpc0: -------------------------------------------------------------------------- Type InUse MemUse HighUse Requests Size(s) temp 2023 431K - 10551 16,32,64,128,256,512,1024,2048,4096,65536,262144,1048576,2097152,4194304,8388608 fpc1: -------------------------------------------------------------------------- Type InUse MemUse HighUse Requests Size(s) temp 2020 431K - 6460 16,32,64,128,256,512,1024,2048,4096,65536,262144,1048576,2097152,4194304,8388608 user@junos> show system virtual-memory |match "fpc|type|temp" fpc0: -------------------------------------------------------------------------- Type InUse MemUse HighUse Requests Size(s) temp 2023 431K - 16101 16,32,64,128,256,512,1024,2048,4096,65536,262144,1048576,2097152,4194304,8388608 fpc1: -------------------------------------------------------------------------- Type InUse MemUse HighUse Requests Size(s) temp 2020 431K - 6665 16,32,64,128,256,512,1024,2048,4096,65536,262144,1048576,2097152,4194304,8388608 user@junos> show system virtual-memory |match "fpc|type|temp" fpc0: -------------------------------------------------------------------------- Type InUse MemUse HighUse Requests Size(s) temp 2023 431K - 21867 16,32,64,128,256,512,1024,2048,4096,65536,262144,1048576,2097152,4194304,8388608 fpc1: -------------------------------------------------------------------------- Type InUse MemUse HighUse Requests Size(s) temp 2020 431K - 6858 16,32,64,128,256,512,1024,2048,4096,65536,262144,1048576,2097152,4194304,8388608 This issue affects Juniper Networks Junos OS: 16.1 versions prior to 16.1R7-S6; 17.1 versions prior to 17.1R2-S11, 17.1R3-S1; 17.2 versions prior to 17.2R2-S8, 17.2R3-S3; 17.2X75 versions prior to 17.2X75-D44; 17.3 versions prior to 17.3R2-S5, 17.3R3-S6; 17.4 versions prior to 17.4R2-S5, 17.4R3; 18.1 versions prior to 18.1R3-S7; 18.2 versions prior to 18.2R2-S5, 18.2R3; 18.2X75 versions prior to 18.2X75-D33, 18.2X75-D411, 18.2X75-D420, 18.2X75-D60; 18.3 versions prior to 18.3R1-S5, 18.3R2-S3, 18.3R3; 18.4 versions prior to 18.4R2-S2, 18.4R3; 19.1 versions prior to 19.1R1-S3, 19.1R2; 19.2 versions prior to 19.2R1-S3, 19.2R2. This issue does not affect Juniper Networks Junos OS 12.3 and 15.1. Weakness: CWE-401 (Missing Release of Memory after Effective Lifetime), CWE-400 (Uncontrolled Resource Consumption) ## Which versions are affected by CVE-2020-1625? It affects 1 product. Products: Juniper Junos. ## How do I fix CVE-2020-1625? No fix has been published for CVE-2020-1625 yet. Limit exposure of the affected software until one is available. ## Is CVE-2020-1625 being exploited? There is no known exploitation of CVE-2020-1625 in the wild and no public exploit code. ## Other vulnerabilities in Juniper Junos - [CVE-2023-36845](https://insights.sbomify.com/CVE-2023-36845/): Juniper Junos OS EX Series and SRX Series PHP External Variable Modification (critical 9.8, exploited in the wild) - [CVE-2020-1631](https://insights.sbomify.com/CVE-2020-1631/): Juniper Junos OS Path Traversal (high 8.8, exploited in the wild) - [CVE-2025-21590](https://insights.sbomify.com/CVE-2025-21590/): Juniper Junos OS Improper Isolation or Compartmentalization (medium 6.7, exploited in the wild) - [CVE-2023-36851](https://insights.sbomify.com/CVE-2023-36851/): Juniper Junos OS SRX Series Missing Authentication for Critical Function (medium 5.3, exploited in the wild) - [CVE-2023-36844](https://insights.sbomify.com/CVE-2023-36844/): Juniper Junos OS EX Series PHP External Variable Modification (medium 5.3, exploited in the wild) ## Fix prompt for AI coding agents ```text Check this codebase for CVE-2020-1625 and fix it if it is affected. What it is: CVE-2020-1625 is a medium-severity denial of service vulnerability in Juniper Junos, published on 8 Apr 2020. It can only be exploited from the same machine or local network, with no action from the victim. Exploitation: There is no known exploitation of CVE-2020-1625 in the wild and no public exploit code. Affected product: Juniper Junos. No package-level version data is available, so check the vendor advisory linked from the reference page. Task: 1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies. 2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it. 3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead. 4. Run the tests and summarise what changed and why. 5. If nothing in the project is affected, say so and change nothing. Reference: https://insights.sbomify.com/CVE-2020-1625/ (Markdown: https://insights.sbomify.com/CVE-2020-1625/index.md) ``` ## Sources - CVE record: https://www.cve.org/CVERecord?id=CVE-2020-1625 - NVD: https://nvd.nist.gov/vuln/detail/CVE-2020-1625 - OSV: https://osv.dev/vulnerability/CVE-2020-1625 --- From sbomify Insights: https://insights.sbomify.com/CVE-2020-1625/ Summaries are generated and may contain mistakes; the official description above is the record.